Laboratory testing for lyme disease: Possibilities and practicalities

Abstract

Laboratory testing in support of the clinical diagnosis of LD is indicated for some patients assessed to have a moderate to high risk of acquiring the disease based on exposure history and objective clinical signs and symptoms. Typical primary or secondary EM can be treated empirically and does not require laboratory confirmation. Culture isolation of B. burgdorferi sensu lato from skin can be accomplished in a clinically relevant time frame and should be considered for atypical EM and for EM-like lesions in patients from areas of nonendimicity. Supplemental immunoserologic testing is indicated for symptomatic patients at significant risk for extracutaneous LD. In the United States, the CDC two-step protocol (ELISA or IFA assay with confirmation of positive or equivocal results by immunoblotting) improves specificity and provides sufficient information to allow rational patient management decisions in the majority of cases. Detection of natural B. burgdorferi sensu lato infection in OspA-vaccinated patients is problematic with many of the presently available ELISA and IFA tests. Molecular-based tests hold promise for improving diagnostic accuracy and decreasing turnaround time for results. However, assessment of the probability of borrelial infection is equally important for PCR-based tests as it is for immunoserologic assays. The ability to detect specific B. burgdorferi sensu lato DNA in the synovial fluid of treated patients with Lyme arthritis can help to distinguish active infection from persistent symptoms due to an immunologic mechanism.